A conventional paper punch is disclosed in FIGS. 5 and 6, and generally includes a case 60 with a floor board 61 through which three slots 62 are defined and three movable frames 80 are movably connected to the floor board 61 by connecting a plate 82 located an outside of the floor board 61 to the respective one of the movable frames 80 by screws. Each movable frame 80 includes front and rear upright walls 801 and a recess 81 is defined in the front upright wall 801. Three punch units 90 are connected on the floor board 61 and located in front of the three movable frames 80. Each punch unit 90 includes a punch frame 91 and a punch member 92 extends through three upright walls on the punch member 92. A spring 93 is mounted to the punch member 92 and a slot 94 defined between the first and second upright walls so as to receive sheets to be punched. An rear end of the punch member 92 extends through the third upright wall of the punch frame 91 corresponding thereto and movably engaged with the recess 81 in the movable frame 80 corresponding thereto. A driving mechanism 70 includes a shaft 75 rotatably connected between two sidewalls of the case 60 and an active gear 74 is connected to one of two ends of the shaft 75. A motor 71 is located in the case 60 and includes an output shaft 711 to which a first passive gear 72 is connected. A second passive gear 73 is engaged between the first passive gear 72 and the active gear 74. A plurality of rings 76 each have an eccentric hole 761 defined therethrough and the shaft 75 extends through the eccentric holes 761 of the rings 76 by clips 77. The eccentric holes 761 are not in aligned with each other and each ring 76 further includes multiple pushing surfaces 762 defined in a periphery thereof and is located in one of the movable frames 80. A gap is defined between the ring 76 and the rear end of the punch member 92.
Referring to FIGS. 7A to 7D, when the shaft 75 is rotated by activating the motor 71, the rings 76 are rotated with the shaft 75 and one of the pushing surfaces 762 of each of the rings 76 pushes the punch member 92 in a pre-set sequence to punch the sheets in the slot 94 in the three punch frames 91. This arrangement can prolong the term of use of the punch members 92 and the punching action is more effective. Nevertheless, when the pushing surfaces 762 of the rings 76 impact the punch members 92, noise is generated and wearing between the pushing surfaces 762 of the rings 76 and the punch members 92.
The present invention intends to provide an electric punch wherein the rings are rotatably received in rectangle pieces which are movably engaged between the two upright walls of the movable frames, the rectangle pieces can only movable in an upright direction so that no impact between the rectangle pieces and the two upright walls of the movable frames.